The present invention relates to a balancer apparatus for suppressing vibrations in an engine and, more particularly, to a compact balancer apparatus which suppresses or cancels out inertial force and/or inertial couple forces induced by pistons, connecting rods, shafts and the like when the engine is running.
When individual movable portions of an engine become off balance during operation, vibrations occur. Such vibrations generate noise, contribute to wear, and may be felt by the operator or occupants of a vehicle containing the engine. To reduce these vibrations, a balancer assembly is typically used to cancel or suppress vibrations of the engine. The balancer assembly operates by providing vibrations opposite to the engine vibrations so that the vibrations cancel each other or reduce the overall magnitude of the engine vibrations.
The balancer assemblies include balancers that produce measured vibrations. Most balancer assemblies include at least two shafts wherein one of the shafts is driven by the crank shaft and the other shaft is driven by either the crank shaft or the other balancer. The vibrations produced by the balancer assemblies are measured for time and intensity. To effectively cancel or reduce the effect of an engine vibration, the vibration produced by the balancer assembly is timed to occur at the same time the engine vibration is expected to occur. More specifically, the vibration produced by the balancer assembly is opposite in magnitude to the engine vibration so that the vibrations cancel each other or the vibrations produced by the balancer assembly causes an overall reduction in vibrations. The intensity of the vibration produced by the balancer assembly is generally determined by the mass of the balancers, which is set by the radius and length of the balancer. Each of the balancers is generally symmetrical with one gear and an identical balance weight to provide calculated countering or suppression vibrations.
One problem with existing balancer assemblies is that the mass required to produce sufficient vibrations makes it difficult to assemble a compact balancer assembly for use in today's compact engines and engine compartments. Most balancer assemblies include balancers with radiuses or lengths that are too large to be easily configured for today's compact engines and engine compartments or are not as effective as desired in reducing engine vibrations. Most balancers are long, bulky, and heavy. Therefore, there is a need for a compact balancer assembly that has sufficient mass to provide sufficient cancellation or suppression of engine vibrations while yet fitting into compact engine compartments.
Another problem with many existing balancer shafts is that the long, bulky, and heavy balancers require bulky, heavy and rigid housings. With the balancers being placed in a housing, and that housing being generally placed within an oil sump, the balancer assemblies, including the housing, require a large portion of the volume of the oil sump on today's compact engines. This may require an increased oil sump size, which may cause problems in today's space restricted engine compartments. Another problem is that due to a large housing, especially when the oil sump has been designed to fit within a compact engine compartment, the maximum oil volume that can be filled into the oil sump is generally less than desired due to the large portion of the oil sump volume required by the housing. The housing for the balancers may also restrict the movement of airflow in and above the oil sump and thereby potentially causes significant power reduction in the engine.